Instrument lighting



26; I v I ':J.'B. DICKSON I 2,452,294

iNSTRUMENT LIGHTING Filed July 16.1945

-. W I IN T 7 pic/{501 BYMWM Patented Oct. 26, 1948 INSTRUMENT LIGHTING John B. Dickson,

to Chrysler Corporation a corporation of Delaw Highland Park, Mich, :assignor Highland Park, Micln, are

Application July 16, 1945, Serial No. 605,202

2 Claims. l This invention relates to improvements in instrument lighting.

An object of the invention is the provision of a simple and eiiicient system for lighting an instrument or a panel mounting a plurality of indicating dials to be illuminated, and to provide a system which is substantially free from glare and reflected shadows.

Another object of the invention is the provision of a lighting system in which light rays are conducted from a suitable source and diffused from the conductor at one or more selected locations for the purpose of illumination.

A further object of the invention is the provision of a lighting system having the foregoing characteristics and including components which are securely mounted in operative position with respect to the objects to be illuminated and are afforded substantial protection against damage from external sources.

Other objects and advantages of the invention will be more apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a side elevational view of a panel mounting a plurality of dial faces illuminated by the improved system.

Fig. 2 is an enlarged, fragmentary horizontal section taken as indicated by the line 2-2 of Fig. 1.

Fig. 3 is an enlarged, fragmentary vertical section taken as indicated by the line 3-3 of Fig. 1.

Referring to the drawings, the invention is illustrated and described in conjunction with a panel 5 mounting a plurality of indicating dials 6 each having a face to be illuminated. Such panel and dials may be those commonly found in motor vehicles and for compactness the dials are arranged in two rows, each of which is provided with the improved system of illumination. The typical system for the lower row includes a pair of spaced electrical lamps, one of which is shown at i inserted in a socket which is mounted on the panel 5 and suitably connected with a source of energy such as a storage battery, not shown. Each lamp 1 is protected and enclosed by a housing 8 detachably secured to the panel 5 by fasteners 9. Each housing 8 has an opening lfll registering with a short sleeve ll secured to the housing.

A transparent rod l2 extends between the housing 8 and is positioned immediately above the row of dials 6, opposite end portions being respectively supported in the sleeves H. A tubular casing l3 encloses the rod l2 and has end emitted at the selected locations.

. 2 portions thereof respectively telescoping the sleeves l l and detachably fixed thereto by a clamp I l. The rod [2 may be formed of clear plastic or glass and has each end face thereof disposed to receive light rays. from the adjacent source lamp 7. The rod l2 has the external surface thereof so polished that light rays received at each end face are conducted lengthwise of the rod by internal reflection thereof.

The faces of the dials are illuminated by causing light rays to be emitted from the rod at locations intermediate the ends thereof and respectively registering with such faces. For this purpose there is provided an optical interruption at a portion of the rod surface at the above locations and as illustrated this interruption is accomplished by a coating l5 preferably, though not necessarily, of paint in optical contact with the rod surface. The surface portion so coated constitutes a light diffusing surface by which light is reflected externally of the rod. Diametrically opposite each such coated portion, the tubular casing i3 is provided with an elongated opening it for the passage of externally reflected light therethrough onto the registering dial face 6.

While the optical interruption may be accomplished by notching or etching the rod surface, I nevertheless prefer a coating in optical contact with the surface as the same may be economically applied and does not permit the escape of light rays as results from notching or etching. The coating so applied may be the same color at all locations or of different colors at selected locations to correspondingly change the color of light The area of the coated surface portions may be relatively varied to thereby increase or decrease the intensity of the lighting of the difierent dials.

The light conducting rod l2 may have a cross section other than round as shown and the casing l3 therefor may be correspondingly varied. This casing is light impervious and prevents the escape of stray light rays and serves as a shield for the diffusing surface when the latter acts as a light source, secondary to the primary source 1.

Although but one specific embodiment of the invention has herein been shown and described, it will be understood that various changes in the size, shape and arrangement of parts may be made without departing from the spirit of the invention.

I claim:

1. In a panel including a plurality of dial faces to be illuminated, a source of light mounted on said panel, a housing for said source having an opening, a sleeve carried by said housing in registration 'with' said opening, a transparent rod arranged lengthwise in juxtaposed relation to said dial faces and having one end thereof disposed at said casing opening to receive light rays from said source and supported in said sleeve. said rod having an external surface for optically transmitting light rays from said one rod end toward the other end by internal reflection thereof, a coating of paint in optical contact with selected portions of said rod surface respectively registering with said dial faces operable to effect reflection of light rays externally of said rod at locations thereof opposite said painted surface portions, and a light impervious casing for said rod having an end portion telescoping said sleeve for support thereby and having openings therein at said locations for the passage of externally reflected light rays, and otherwise constituting a shield for said rod throughout the length thereof including said coated surfaces.

2. In a panel including a plurality of dial faces to be illuminated, a source of light, a transparent rod arranged lengthwise in juxtaposed relation to said dial faces and having one end thereof disposed to receive light rays from said source, said rod having an external surface operable to trans- 4 i mit rays lengthwise of said rod by internally reflecting the same, axially spaced optical interruptions on said external surface respectively registering with said dial faces and operable to eflect reflection of light rays externally of said rod at locations thereof opposite said optical interruptions, and a light impervious casing for said rod having openings therein at said locations for the passage of externally reflected light rays, and otherwise constituting a shield for said rod throughout the length thereof including said optical interruptions.

JOHN B. DICKSON.

REFERENCES CITED The following references are of record in the file of this patenti UNITED STATES PATENTS Number Name Date r 2,188,821 Rylsky Jan. 30, 1940 2,207,117 Collins July 9, 1940 2,214,595 Rights Sept. 10, 1940 FOREIGN PATENTS Number Country Date 236,863 Great Britain July 16, 1925 

